The invention relates to a resonator comprising first and second balanced integrators each having a non-inverting and an inverting input terminal, as well as a non-inverting and an inverting output terminal, first and second coupling circuits between the non-inverting output terminal of the first integrator and the non-inverting input terminal of the second integrator and between the inverting output terminal of the first integrator and the inverting input terminal of the second integrator, respectively, and feedback circuits between the non-inverting output terminal of the second integrator and the inverting input terminal of the first integrator and between the inverting output terminal of the second integrator and the non-inverting input terminal of the first integrator, respectively.
U.S. Pat. No. 4,926,135 discloses a balanced integrator-filter arrangement. An active RC filter consists of a balanced amplifier in combination with various resistors and capacitors; it can be extended to obtain an n-th order filter arrangement. Once an n-th order filter arrangement has been obtained, it can be modified to obtain various special purpose filters, such as a low-pass, a high-pass or an all-pass n-th order active RC filter by merely changing the values of the resistors and capacitors.
It is, inter alia, an object of the invention to provide a resonator in which the tuning frequency and/or the dynamic range are improved over prior art resonators. To this end, the invention provides a resonator as defined in the independent claim. Advantageous embodiments are defined in the dependent claims.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.